Just to get discussion going again. Talking with several folks I have heard several concerns expressed about the proposal. I think it would be good if these (and others) could be raised on the list, so we can start discussion. We can continue this next week in Chicago, but Vinod will not be able to make this meeting, so an e-mail discussion will help. Here are the issues I have hear of so far: - May not work well on current h/w that is not cache coherent, as it requires a remote thread in this case. I believe this is for the SX series of machines, but Jesper please correct me if I am wrong here. What would be an alternative approach that could provide expected performance on platforms that may require work on the remote end for RMA for correctness, and work well on platforms that do require very specific remote cache management (or other actions) for correctness ? - Concern about future high-end platforms, under that assumption that these will not be cache coherent (and will actually have caches ­ if they don¹t this is not a concern), and therefore this proposal is aimed at a short-lived technical capability. - What is missing ? Rich On 9/6/08 6:06 PM, "Vinod tipparaju" <[email protected]> wrote:

Rajeev,

Excellent questions.

Technically, yes. However, ARMCI does more thinking about Global Arrays. Particularly because of stride data transfers (multiple stride levels). However, I don't see why we cannot have an alternative port. The only way to know is to prototype the interfaces, implement Global Arrays on top of them and see how the interfaces fare. From superficial thinking, I think they will do just fine ;-). We however cannot say this about all potential implementations.

I am not sure if Dan Bonachea is a member of this list. I will write him a message if he isn't.

Thanks, Vinod.

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From: [email protected] To: [email protected] Date: Sat, 6 Sep 2008 16:24:35 -0500 Subject: Re: [Mpi3-rma] draft of a proposal for RMA interfaces

Vinod, Thanks for the proposal and the nice presentation. A question I had was does it meet the needs of the Global Arrays library? That is, if this were available in MPI today, would you implement Global Arrays with MPI and nothing else (not ARMCI). Similarly, it would be good to run it by Dan Bonachea and see what he has to say regarding implementing UPC.

Regards, Rajeev

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-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Vinod tipparaju Sent: Thursday, September 04, 2008 1:50 AM To: [email protected] Subject: [Mpi3-rma] draft of a proposal for RMA interfaces

Folks,

Attached is a draft of a new proposal for MPI3-RMA interfaces for your perusal.

Thanks, Vinod Tipparaju, ORNL.

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